JP4004685B2 - Light monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical monitoring device that monitors the displacement and deformation of a monitoring object such as a natural object or an artificial structure.
[0002]
[Prior art]
In recent years, as a method for observing a continuous optical loss distribution in the longitudinal direction of an optical fiber, there is a method using the fact that the intensity of Rayleigh scattered light, which is one of optical fiber backscattering phenomena, depends on the optical loss of the optical fiber. It has been developed and put into practical use and is being applied to various sensing applications. However, in displacement monitoring and deformation monitoring of various natural objects and man-made structures, there are cases where a large number of monitoring targets are dispersed over a wide range. In such a case, for monitoring each monitoring target efficiently. The current situation is that there is no appropriate one and development is required.
[0003]
[Problems to be solved by the invention]
As an optical fiber sensor for monitoring deformation of natural objects and man-made structures, etc., it is excellent in workability such as mounting on the monitored object, and the displacement and deformation of the monitored object is efficiently applied to bending or breaking of the optical fiber. There is a demand for a structure to act, and until now, there has been no suitable structure that satisfies these conditions. Furthermore, there is a demand for cost reduction, and it is necessary to develop an optical fiber sensor that satisfies these conditions.
[0004]
The present invention has been made in view of the above-described problems, and can detect a wide range of displacement and deformation of a monitoring object such as a natural object or an artificial structure, and can be easily monitored at a low cost. It is an object of the present invention to provide an optical monitoring device.
[0005]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the present invention is an optical monitoring device that monitors the displacement or deformation of a monitoring object such as a natural object or an artificial structure with light, and is installed on the monitoring object so that the monitoring object The optical fiber of the optical fiber sensor that causes breakage or deformation in the optical fiber due to displacement or deformation is a single fiber.Optical cableOr a part of a plurality of optical fibers of a communication line formed by assembling a plurality of optical cablesIs connected to an optical fiber assigned as a monitoring dedicated line, and a connection point between the optical fiber of the optical fiber sensor and the optical fiber of the monitoring dedicated line is accommodated in a branch connection body installed in the middle of the communication line. As a maintenance dedicated line, an inundation detection module for detecting inundation or a temperature detection module for temperature detection provided inside the branch connection body is another part of the plurality of optical fibers of the communication line. Connected to the assigned optical fiber, including the optical fiber for the monitoring dedicated line and the optical fiber for the maintenance dedicated lineThe plurality of optical fibers on the optical cable side can be switched and connected to an optical pulse tester, and the optical fiber on the optical fiber sensor side is connected to the optical pulse tester via the optical fiber of the communication line. An optical monitoring device characterized in that the optical monitoring device is connected so as to be able to be incident is used as the means for solving the problems.
[0006]
In the present invention, an optical fiber on the optical fiber sensor side is connected to an optical pulse tester using an optical fiber of a communication line, and an abnormality in the installation location of the optical fiber sensor, that is, various natural objects and artificial structures are monitored. Monitor the occurrence of displacement and deformation of the object (monitoring abnormalities). The abnormality is monitored by detecting that the optical fiber incorporated in the optical fiber sensor has undergone deformation such as breaking or bending. The breakage or deformation of the optical fiber can be detected from the observation result of the return light of the incident light from the optical pulse tester. The optical pulse tester performs switching of the plurality of optical fibers on the optical cable side so that the test light is incident on each optical fiber and the return light is observed (optical test). As a result, an optical test is performed on the entire optical line including the optical fiber connected to the optical pulse tester and the optical fiber connected to the optical fiber. The test light is incident through the optical fiber and an optical test is performed.
[0007]
As is well known, when light is incident on an optical fiber, it is caused by light scattering (Rayleigh scattering) due to Fresnel reflected light at a breakage point of the optical fiber or a connector connection point, or a small non-uniformity such as the density of the optical fiber. It is known that backscattered light returns to the incident end of the optical fiber, and the time from when the test light is incident on the optical fiber from the optical pulse tester (so-called OTDR) until the return light is received (hereinafter, By measuring the “return time”), the position of the break point (distance from the optical pulse tester) can be grasped. Usually, only the return light due to light scattering inherent in the optical fiber, such as backscattered light of Rayleigh scattered light, is observed from the optical fiber. For example, when this optical fiber breaks, from the optical pulse tester to the breaking point. The back scattered light of the Rayleigh scattered light and the strong Fresnel reflected light from the breaking point are observed by the optical pulse tester, and the back scattered light of the Rayleigh scattered light from the optical fiber after the breaking point is not observed. Thereby, the break of the optical fiber is detected, and the position of the break point can be grasped from the return time of the return light of the Fresnel reflected light.
Even if the optical fiber is not broken, when the optical fiber is deformed, for example, the optical fiber is bent sharply, and it is possible to detect the bent portion by observing an increase in light loss at the bent portion. is there. In addition, an increase in optical loss is also observed due to the collapse of the optical fiber in the cross-sectional direction. In other words, from the point where the intensity of the return light is observed to be abruptly changed by the optical pulse tester (the return time of the return light to the optical pulse tester), the presence of the deformed part such as a bent optical fiber and its position are determined. I can grasp.
[0008]
The optical fiber sensor applied to the optical monitoring apparatus of the present invention causes the optical fiber to undergo deformation such as breakage and bending due to the occurrence of displacement and deformation of the monitoring object such as various natural objects and artificial structures. Therefore, it is possible to detect the displacement or deformation of the monitored object by detecting the breakage or deformation of the optical fiber by the optical pulse tester.
The breaking or bending of the optical fiber is detected by observing Fresnel reflected light from the breaking point of the optical fiber or observing an increase in loss.
[0009]
For example, when an optical fiber of an optical fiber sensor breaks, Fresnel reflected light from the break point is observed, an increase in loss at a bent point, etc. is observed, or return light from the optical fiber after the break point is observed. When it disappears, displacement, deformation, collapse, etc. of the monitoring object on which this optical fiber sensor is installed are detected. In addition, it is possible to grasp the breaking position of the optical fiber for each installation position of the optical fiber sensor from the return time of the Fresnel reflected light, etc., and thereby the occurrence position of the displacement, deformation, collapse, etc. of the monitored object Can be grasped. Depending on the cross-sectional shape of the broken optical fiber at the breaking point, Fresnel reflected light with sufficient intensity may not be generated, but the presence or absence of return light from the optical fiber after the breaking point and an increase in loss are also observed. Thus, it is possible to reliably grasp the presence / absence of a break point and the presence / absence of an optical fiber deformation portion.
As described above, in the present invention, it is possible to detect the occurrence of displacement, deformation, collapse, etc. of the monitored object by detecting a deformed portion such as a broken or bent optical fiber, and return to the optical pulse tester. By measuring the position of the break point of the optical fiber and the position of the bent part from the return time of the light, the occurrence point of displacement, deformation, collapse, etc. can be grasped.
[0010]
By the way, in the construction of a high-speed information communication network, the installation of optical cables using roads, railroad tracks, and river dikes has been rapidly expanding. It is suitable to connect the optical fiber of the optical fiber sensor to the optical pulse tester using the optical cable. The optical cable usually contains a large number of optical fibers, and unused optical fibers are often stored for the purpose of future expansion of communication lines. In the present invention, a part of the optical fiber of the optical cable for communication is used as a dedicated line for monitoring, and the optical fiber of the optical fiber sensor is connected to be used for connection between the optical fiber of the optical fiber sensor and the optical pulse tester. The structure of the optical cable for communication is not affected, and a normally used optical cable can be used as it is.
[0011]
In optical lines for communication, maintenance such as discovery of abnormalities such as disconnection (line monitoring) and restoration is performed by optical tests using an optical pulse tester. Specifically, for example, while selectively switching and connecting each optical fiber of the optical cable to the optical pulse tester, the test light is incident on each optical fiber, and Fresnel reflected light and loss increase from the return light. Observe. If Fresnel reflected light or increased loss is observed, it is understood that the optical fiber has undergone deformation such as breakage, bending, or crushing. In addition, it is possible to monitor whether or not the connection state is reliably maintained by observing Fresnel reflected light and an increase in loss at connection locations such as connector connection locations by optical connectors and fusion splicing of optical fibers.
In the present invention, since the optical fiber of the optical fiber sensor is connected to the optical pulse tester using the optical fiber of the optical cable, the optical fiber sensor has any configuration that causes deformation such as breakage or bending in the optical fiber. In addition, it is possible to detect breakage and bending deformation of the optical fiber of the optical fiber sensor by normal line monitoring of the communication optical cable.
[0012]
According to a second aspect of the present invention, in the optical monitoring apparatus according to the first aspect, the optical fiber of the communication line and the optical fiber of the communication line are obtained from the observation result of the return light of the test light incident on the optical fiber of the communication line to the optical pulse tester. A detection unit that detects an abnormal point that causes breakage or deformation of the optical fiber on the optical fiber sensor side, and a display unit that displays a position of the abnormal point based on a command from the detection unit, To do.
According to the present invention, both the information indicating the position of the abnormal point detected from the optical fiber of the optical cable for communication and the information indicating the position of the abnormal point detected from the optical fiber of the optical fiber sensor are both from the detection unit. Based on the command, it is displayed on the same display unit. For this reason, the position of the abnormal part can be easily grasped about the entire optical line including the optical fiber of the optical fiber sensor.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the optical monitoring apparatus of the present invention will be described below with reference to the drawings.
The optical monitoring devices of the first and second embodiments are for monitoring the displacement and deformation of a monitoring object such as various natural objects and artificial structures, both of which are displacements of monitoring objects scattered in a plurality of locations. In addition, it monitors partial deformation of a large monitoring object.
1 and 3, reference numeral 1 is an optical monitoring device, 2 is a road, 3 and 4 are transmission devices, 5 and 6 are optical cables, 7 is a monitoring unit, 8 is an information box, 9 is a closure, 10a and 10b are monitoring An object 11 is an optical fiber sensor.
For example, a single mode optical fiber having a core diameter of several μm to 10 μm and a diameter of 125 μm is employed as the optical fiber 12 incorporated in the optical fiber sensor 11 of each of the following embodiments. As the OTDR which is the optical pulse tester 50, for example, a high resolution type having a test light wavelength of 1310 nm, a pulse width of 10 ns or more (as fine as possible), and a spatial resolution of 2 m or more (as short as possible) is adopted.
[0014]
(First embodiment)
In the optical monitoring device 1 of FIG. 1, one or a plurality of optical fibers 12 (2 in FIG. 1) are installed so as to extend over an area where the monitoring objects 10a and 10b exist (hereinafter referred to as “monitoring area 10c”). Optical fiber sensors 11 are installed at a plurality of locations. Specifically, in FIG. 1, the optical fibers 12 are respectively inserted from both ends of one protective tube 12a laid so as to stretch over the monitoring target region 10c, and two wires are provided over almost the entire length of the protective tube 12a. The optical fiber 12 is accommodated.
[0015]
The optical fiber sensor 11 is configured to cause deformation such as breakage or bending in the optical fiber 12 due to local deformation of the monitoring object 10a or displacement between the monitoring objects 10b, and various structures can be employed. . For example, it is installed in a place where the monitoring object 10a is likely to be deformed, and the relative displacement of two different places of the monitoring object 10a due to the deformation of the monitoring object 10a is applied to the protective tube 12a to the optical fiber 12. A configuration that causes breakage or deformation, a configuration that causes breakage or deformation in the optical fiber 12 by applying a relative displacement between adjacent monitoring objects 10b to the protective tube 12a, or the like can be employed.
[0016]
  As shown in FIG. 1, in the information box 8 installed in the middle of the optical cables 5 and 6 constituting the communication line connecting the transmission devices 3 and 4, for example, a branch connection body that is a closure 9 is installed, For example, hundreds of fibers or thousands of fibers (multi-core) optical fibers 17 and 18 accommodated in the optical cables 5 and 6 are connected to each other via a connection point 20 to communicate between the transmission devices 3 and 4. Configure the line. A part of the optical fiber 17 of the optical cable 5 is assigned as a dedicated monitoring line for the monitoring objects 10a and 10b (referred to as “optical fiber 17a” for convenience of description), and the optical fiber 17a includes a closure 9. The optical fiber 12 on the optical fiber sensor 11 side is the connection point19Connected through. Further, another part of the optical fiber 17 of the optical cable 5 is a maintenance dedicated line (connected to the water detection module 40 for detecting water in the information box 8 or the closure 9 and the temperature detection module for detecting temperature). For convenience of explanation, it is assigned as “optical fiber 17b”. In FIG. 1, one end of the optical fiber 41 of the inundation detection module 40 installed in the closure 9 is connected to the optical fiber 17b, and the other end of the optical fiber 41 is connected to the optical fiber 18 on the optical cable 6 side via the connection point 21, respectively. By being connected, the optical fibers 17 b and 18 of the optical cables 5 and 6 are connected via the optical fiber 41.
  In addition, since it is the optical cable 12b from the monitoring object area | region 10c of the optical fiber 12 to the closure 9, it is excellent in laying workability | operativity. Further, the optical fiber 12 may be connected to the optical fiber of the optical cable 12b in the vicinity of the monitoring target region 10c via a branch connection box or the like.
[0017]
In FIG. 1, the connection point 19 between the optical fiber 17a and the optical fiber 12 of the monitoring dedicated line is a fusion splice, and the connection point 20 between the optical fiber 17 on the optical cable 5 side and the optical fiber 18 on the optical cable 6 side is Connector connection by the optical connector 22, the connection point 21 between the optical fiber 17b of the maintenance dedicated line and the optical fiber 41 on the inundation detection module 40 side are fusion-bonded, but the connection points 19, 20, 21 are described above. The present invention is not limited to the configuration, and a fusion splicing portion, a connector connection, or the like may be appropriately selected and applied. However, since the connector connection is excellent in terms of connection workability, it is advantageous in this respect that the connection points 19 and 21 are also connector connections.
[0018]
In addition, it is possible to secure a free optical fiber that is not connected anywhere in the optical cable 5 in view of future expansion of communication lines.
In FIG. 1, the closure 9 installed in the information box 8 is illustrated as a branch connection body. However, as the branch connection body, a closure provided directly on the optical cables 5 and 6 without using the information box 8, for example, an aerial optical cable. In this case, there is no change in the function or the like for storing the connecting portion between the optical fibers. Further, the branch connection body is not limited to the closure, and various configurations such as a branch connection box, a termination box, and an optical wiring board can be adopted.
[0019]
By the way, the optical cables 5 and 6 are laid by underground burial, aerial laying, and the like, and the installation positions of the information box 8 and the closure 9 are various in the ground, on the ground, in the air, in the building and the like. The information box 8 is often installed in the ground or on the ground. For example, an optical cable laid in the underground conduit is provided using a manhole or a handhole. In particular, the information box 8 that is installed outdoors (including the underground) and the closure 9 that is housed inside the information box 8 should take measures against waterproofing against inundation such as groundwater and rainwater, and measures against abnormal rise in internal temperature due to geothermal heat and sunlight. In view of this, it has been proposed.
The water immersion detection module 40 is configured to bend the optical fiber 41 by using expansion of the hygroscopic swelling material due to water immersion, floating floating due to water immersion, or the like as a driving force. Further, in FIG. 1, the installation position of the inundation detection module 40 is inside the closure 9, but is not limited thereto, and may be installed outside the closure 9 in the information box 8.
The temperature detection module is a sensor for detecting temperature, and has various forms. For example, the optical fiber 41 is bent by using a deformation of a material having a large linear expansion coefficient or a deformation of a bimetal or a shape memory alloy as a driving force. A configuration or the like is adopted. The temperature detection module may be installed inside the closure 9 or outside the closure 9 in the information box 8.
The optical fiber sensor 11, the water immersion detection module 41, and the temperature detection module may all be configured to break the optical fiber, but may be configured to deform such as bending so as not to break the optical fiber. It is preferable in terms of cost reduction for recovery workability at the time of malfunction due to some cause and reuse after abnormality detection.
[0020]
The optical fibers 17a and 17b are connected to the optical pulse tester 50 by the monitoring unit 7 installed at the end of the optical cable 5. Specifically, in FIG. 1, in the monitoring unit 7, the optical fiber 17a is connected to the optical switch 23 via the optical fiber 16 and the optical connector 16a, and the optical fiber 17b is directly connected to the optical switch 23. The switch 23 is selectively connected to the optical fiber tester 50 in units of one core by switching the optical fiber 51 on the optical pulse tester 50 side to the optical fibers 16 and 17b. It has become. Then, test light is incident on the optical fibers 17a and 17b connected to the optical pulse tester 50 to perform an optical test, and disconnections and bendings generated in the optical fibers 17a and 17b and the optical fibers 12 and 41, etc. The occurrence of abnormality can be grasped by detecting the deformation of.
Note that the switching connection and the optical test of the optical fiber 51 on the optical pulse tester 50 side with respect to the optical fibers 17a and 17b by the optical switch 23 and the optical test are sequentially and automatically repeated in a predetermined order. Since the time required for the optical test itself is short, the connection of the optical pulse tester 50 to each of the optical fibers 17a and 17b and the optical test are repeatedly performed continuously, so that the optical line of the optical fibers 17a and 17b is substantially reduced. Continuous monitoring is realized.
[0021]
If an optical test of the optical fibers 17a, 17b, 12, and 41 shows that no Fresnel reflected light or increased loss is observed from a portion other than the backscattered light or light loss occurrence point such as the connection points 19 and 21, the optical fibers 17a, 17b, No abnormality such as disconnection or bending occurs in the optical lines 12 and 41 (the test result is “normal”). However, if Fresnel reflected light or an increase in loss is observed from other than the above locations, it can be seen that the optical fibers 17a, 17b, 12, 41 have abnormalities such as disconnection and bending (the test result is “abnormal detection”). .
Since the position of the abnormal part can be grasped from the return time of the return light by the optical test, it is possible to determine which optical fiber 17a, 17b, 12, 41 has an abnormality.
[0022]
Local displacements, deformations, collapses, and the like of the monitoring objects 10a and 10b are grasped by detecting an abnormal part in the optical fiber 12, and the abnormal part is also detected in the optical fiber 41 due to water in the closure 9. It is grasped by doing.
However, in the monitoring target region 10c, the two optical fibers 12 accommodated in one installed protective tube 12a are broken or deformed by the optical fiber sensor 11 (in the two optical fibers 12). In some cases, only one of them is broken).
If an abnormal location is detected in the optical fibers 17a and 17b, there is a possibility that a failure has occurred due to some cause such as miscutting or mischief of the optical cable 5 due to construction or the like. As a result, the optical test of the optical fibers 12 and 41 can detect the disconnection or abnormal bending of the optical cable 5 for communication. It can also be used for maintenance.
[0023]
In order to connect a plurality of optical fibers 12 installed in the monitoring target area 10c to the optical fibers 17a of the optical cable 5 with the same closure 9, the number of the optical fibers 12 in the optical fiber 17 in the optical cable 5 is the same. The number of cores is assigned as the optical fiber 17a for the dedicated monitoring line, and each optical fiber 17a is connected to the optical switch 23 so that it can be switched and connected to the optical pulse tester 50. In FIG. 1, two (two cores) are connected to the optical fiber 17 of the optical cable 5 for each monitoring target area 10c, and four (four cores) optical fibers 12 are connected. 17 is assigned as the optical fiber 17a for the dedicated monitoring line.
From the result of the optical test of each optical fiber 12 by the optical pulse tester 50, the abnormal part occurring in the monitored region 10c can be grasped for each optical fiber 12, and the position of the abnormal part (from the return time of the return light by the optical test ( The distance from the optical pulse tester 50) can also be grasped for each optical fiber 12. In the monitoring unit 7, an extra length 24 of the optical fiber 16 is secured about 1000 m, and it is possible to monitor the optical line that is close to the monitoring unit 7 and difficult to monitor by the optical pulse tester 50. Yes. Since the optical fiber 16 is detachable from the optical fiber 17a by the optical connector 16a, the optical pulse tester 50 of the optical fiber 12 of the optical fiber sensor 11 can be selected by using the optical fiber 16 having an appropriate length. The distance from can be adjusted.
Note that the end of each optical fiber 12 (the end on the side far from the optical pulse tester 50) is subjected to non-reflection treatment.
[0024]
On the other hand, one optical fiber 17b for the maintenance dedicated line may be secured in the communication optical cable 5, and the presence or absence of an abnormality can be easily determined by an optical test. The terminal 18a on the side far from the optical pulse tester 50 of the optical fiber 18 of the optical cable 6 connected to the optical fiber 17b via the optical fiber 41 of the inundation detection module 40 is usually subjected to non-reflection treatment.
[0025]
FIG. 2 shows an example of the detection unit 52 connected to the optical pulse tester 50. The detection unit 52 uses the received light data of the return light from the optical test of the optical fibers 17a and 17b to cause the position measurement unit 52a to generate significant light loss (light above a certain level) due to the location where the Fresnel reflected light is generated and the bending of the optical fiber. Loss (determination level is set in advance) is grasped in the position (distance from the optical pulse tester 50), and the data read from the database stored in the storage unit 52b and the position measurement unit 52a The comparison part 52c compares and contrasts the position of the abnormal part grasped in this way. That is, in the comparison unit 52c, the backscattered light that can be recognized when the result of the optical test is “normal” is included in the data obtained by the optical test (the position of the abnormal part grasped by the position measuring unit 52a). Compare and contrast whether data other than where the optical loss occurs is included.
[0026]
The data obtained by the optical test and the “normal” data read from the storage unit 52b are output as an electrical signal or the like from the output unit 52d and connected to the detection unit 52 in FIGS. Displayed on the map screen. In addition, the data obtained by the optical test and the “normal” data read from the storage unit 52b are displayed on the display unit 53 so as to be distinguishable with different colors, etc. Even if the area 10c is vast, the position of the abnormal part can be clearly seen on the map screen. On the map screen, in addition to the abnormal part grasped by the optical test of the optical fibers 12 and 41, the abnormal part generated in the optical cables 5 and 6 for communication (abnormalities detected in the optical fibers 17a and 17b). By also displaying the location), it can also be used for failure recovery of the communication line. That is, if an abnormal point such as a disconnection is detected in the optical fibers 17a and 17b, there is a possibility that not only the optical fibers 17a and 17b but also the optical cables 5 and 6 themselves are cut and suddenly bent. Thus, the presence or absence of a failure such as disconnection can be monitored for the optical fiber 17 of the communication line.
The data output from the output unit 52d may be transmitted to the display unit of another management system via the hub 54 (“HUB” in FIG. 2) or the router 55. By displaying the data from the plurality of light monitoring devices 1 in a single display unit, a wider area or a larger number of monitoring target areas 10c can be monitored in one place.
[0027]
Furthermore, it is preferable that the display unit 53 can display, as detailed information, whether or not an abnormality has occurred for each optical fiber sensor 11 for each of the one or more monitoring target areas 10c monitored by the optical monitoring device 1. . That is, in the monitoring target region 10c, the position of the abnormal point is grasped for each of the two optical fibers 12 accommodated in the installed single protective tube 12a. For example, the deformation scale (area, deformation width, etc.) of the monitored object 10a, the number of the monitored objects 10b that have caused the displacement, and the like can be grasped. For example, when monitoring that a plurality of monitoring objects 10a and 10b existing on the ground of the monitoring target area 10c are displaced or deformed due to the fluctuation of the ground or the like, they are stored in the protective tube 12a. From the broken position of the optical fiber 12 and the broken position of the other optical fiber 12, it is possible to roughly grasp the range in which the monitoring target region 10 c is abnormal (the range in which displacement or deformation is generated; hereinafter “abnormal range”). The fracture position is almost equivalent to the width of the abnormal range). When the installation density of the optical fiber sensors 11 in the monitoring target area 10c is increased, the size, shape, etc. of the abnormal range of the monitoring target area 10c can be grasped more finely.
After one optical fiber 12 is broken, monitoring after the breaking point by the optical fiber 12 cannot be performed, but monitoring can be continued by taking observation data from the other optical fiber 12, and as a result, The detection of the displacement of the specific monitoring objects 10a and 10b by the optical fiber sensor 11 existing after the breaking point of one optical fiber 12, the size of the abnormal range of the monitoring target area 10c, etc. From test data.
[0028]
(Second embodiment)
Hereinafter, an optical monitoring device 60 according to a second embodiment of the present invention will be described with reference to FIG.
In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be simplified.
In the optical monitoring device 1 of the first embodiment, line monitoring such as disconnection of a line dedicated for communication is not performed, but in the optical monitoring device 60 of this embodiment, line monitoring of a communication line is also performed. .
In this optical monitoring device 60, the optical fiber 17 on the optical cable 5 side and the optical fiber 3a on the transmission device 3 side are connected through an optical branch box 63 housed in an optical wiring rack 62 provided in the monitoring unit 61, The optical fiber 65 is branched from each optical fiber 17 of the optical cable 5 through an optical branching element 64 such as an optical coupler built in the optical branching box 63. Each optical fiber 65 is connected to the optical switch 23, and the optical switch 51 connects the optical fiber 51 on the optical pulse tester 50 side to each optical fiber 65 so that the optical fiber 17 can be switched. The tester 50 is selectively connected in units of single cores. Test light from the optical pulse tester 50 is incident on the optical fiber 17 through the optical branching element 64 and transmitted to the optical line related to the optical fiber 17, and return light such as backscattered light passes through the optical branching element 64. And return to the optical pulse tester 50 side.
On the other hand, the monitoring dedicated optical fiber 17 a and the maintenance dedicated optical fiber 17 b are directly connected to the optical pulse tester 50 by the optical switch 23 without branching the optical fiber 65 by the optical branching element 63. It has come to be. Further, the extra length 24 of the optical fiber 16 is secured in the same manner as in the first embodiment. However, it is possible to adopt a configuration in which these optical fibers 17a and 17b are connected to the optical pulse tester 50 via the optical fiber 65 branched by the optical branching element 63. For example, in the optical cable 5 When an empty line to which the optical branch box 63 is not connected is assigned as the optical fibers 17a and 17b, the optical branch box 63 is connected and the optical fiber 65 is connected to the optical pulse tester 50. It is possible to function as the optical fibers 17a and 17b only by doing.
[0029]
The test light wavelength used for the optical test is different from the communication wavelength so as not to affect the optical communication. For example, the test light wavelength is 1.55 μm for the communication wavelength 1.31 μm, and the test light wavelength is 1.65 μm for the communication wavelength 1.55 μm.
Further, in the communication line constituted by the optical fibers 17 and 18 of the optical cables 5 and 6 and the optical fiber 3a on the transmission device 3 side, the light interposed between the optical branching element 64 and the transmission devices 3 and 4 respectively. The light of the test light wavelength is cut by the filters 66 and 67 to prevent the test light from entering the transmission apparatuses 3 and 4. In the transmission apparatuses 3 and 4, the influence of communication noise due to the test light is avoided. . In FIG. 3, specifically, the optical filter 66 is incorporated in the optical branching box 63 and interposed in the middle of the optical line connected from the optical branching element 64 to the transmission device 3 side. 4 is interposed in the optical fiber 18 of the optical cable 6 in the vicinity.
[0030]
The switching connection of the optical fiber 51 on the optical pulse tester 50 side to the optical fibers 16, 17 b, 65 by the optical switch 23 and the optical test are successively and automatically repeated in a predetermined order. Since the time required for the optical test itself is short, repeated switching connection of the optical pulse tester 50 to the optical fibers 16, 17b, and 65 and the optical test are carried out repeatedly and substantially, so that the optical fibers 17, 17a, 17b are substantially obtained. Continuous monitoring such as disconnection of the optical line is realized. Thereby, the disconnection and bending of the optical fibers 12 and 41 are also monitored, and it is possible to constantly monitor the deformation and displacement of the monitoring objects 10a and 10b.
That is, according to the optical monitoring device 60, in addition to the optical fiber 17a for the monitoring dedicated line and the optical fiber 17b for the maintenance dedicated line, the optical pulse tester 50 also applies to the optical line related to the optical fiber 17 of the communication line. By performing an optical test, disconnection and the like can be constantly monitored.
[0031]
In FIG. 1 and FIG. 3, the communication line between the transmission devices 3 and 4 is configured by connecting together the multi-core optical cables 5 and 6, but the number of optical cables to be connected may be further increased. The number is not limited. In addition, there are various types of communication lines, such as connection to another communication line, a branching connection by an optical splitter to form a PDS (Passive Double Star) line, and a plurality of optical cables assembled by bundling. It goes without saying that the configuration can be adopted.
The optical cable for communication that is the connection target of the optical fiber 12 on the optical fiber sensor 11 side is not limited to the connection between the transmission apparatuses 3 and 4, for example, an optical cable that connects between the transmission apparatus 3 and the terminal apparatus, etc. Various types of optical communication cables can be used.
[0032]
The optical fiber of the optical fiber sensor may be directly connected to the optical pulse tester 50 or the optical switch 23 without being connected to the optical fiber 17 of the optical cable 5. For example, as the optical fiber of the optical fiber sensor, the optical fiber 17 of the optical cable 5 may be extended from the optical cable 5 to the monitoring target area 10c. In this configuration, the noise observed together with the return light of the optical test can be reduced by reducing the number of connection points, and more accurate monitoring can be performed.
Further, when the communication line between the transmission devices 3 and 4 is a set of a plurality of optical cables, the optical cable branched from an appropriate position can be directly drawn into the monitoring target region 10c as an optical fiber of the optical fiber sensor. It is. In this case as well, the optical cable that becomes the optical fiber of the optical fiber sensor is integrated with another optical cable such as an optical cable containing a communication optical fiber from the optical pulse tester or the optical switch to the middle. The results of line monitoring related to can be used for maintenance of optical cables for communication. Needless to say, even with this configuration, the monitoring accuracy can be improved by reducing the number of connection points.
[0033]
  If the number of optical cables that make up the communication line is not only two optical cables 5 and 6, but more, the number of information boxes 8 and branch connections installed in the middle of the communication line may increase. For example, the optical fiber 18 on the optical fiber sensor 11 side or the optical fiber 41 of the inundation detection module 40 is connected to the optical fiber 18 of the optical cable 6 at a branch connection body installed at a terminal far from the optical pulse tester 50 of the optical cable 6. Are connected, a part of the many optical fibers 18 in the optical cable 6 are allocated to the monitoring dedicated line and the maintenance dedicated line. The optical cable for the monitoring dedicated line on the optical cable 6 side and the optical fiber 18 of the maintenance dedicated line The connection of the optical fiber 17 on the 5 side need not be changed. Further, even when a branch connector such as a closure is installed on the side far from the optical pulse tester 50 via another optical cable for communication connected to the optical cable 6, the connection between the optical fibers between the optical cables for communication is the same. It is. Thus, the optical fiber 12 connected to the optical fiber of the communication line at a location farther from the optical pulse tester 50 than the closure 9 is also connected to the optical pulse tester 50 via the optical fiber of the optical cable of the communication line. .
  In addition, it is preferable to connect the optical fibers of the ingress detection module 40 and the temperature detection module installed in a plurality of installed branch connections or information boxes in series via the optical fibers of the optical cables 5, 6. In this case, only one of the communication lines constituted by the optical cables 5, 6... Needs to be assigned as a maintenance dedicated line, and more of the optical fibers in the optical cables 5, 6. Can be assigned to a dedicated monitoring lineit can.
[0034]
The optical monitoring devices 1 and 60 of the first and second embodiments can be simply configured by simply connecting the optical fiber 12 of the optical fiber sensor 11 to the optical fibers of the optical cables 5, 6... The monitoring objects 10a, 10b existing at a plurality of locations can be monitored for displacement, deformation, collapse, etc. at a single monitoring location installed at a location away from the monitoring objects 10a, 10b. Moreover, at the monitoring location, the monitoring object 10a, 10b of each place where the optical fiber sensor 11 is installed is determined by information displayed on the display unit 53, an alarm issued when the detection unit 52 detects an abnormal location, or the like. Displacement, deformation, collapse, etc. can be grasped immediately. Further, by installing a branch connector such as a closure 9 at an appropriate position of the optical cables 5, 6... And connecting the optical fiber 12 of the optical fiber sensor 11 to the optical fibers of the optical cables 5, 6. The fiber sensor 11 can be freely performed. That is, when the monitoring target region 10c is distributed at a plurality of locations along the optical cables 5 and 6, a configuration in which the optical fiber 12 of the optical fiber sensor 11 is branched from a plurality of locations on the communication line can be employed. is there. Further, it is possible to adopt a configuration in which a multi-core optical cable is branched from the communication line as the optical fiber 12 and further branched into a plurality of optical fibers 12 after the branching.
[0035]
Furthermore, since a plurality of optical fiber sensors 11 can be monitored by the same optical fiber 12, the cost can be reduced, and a wide range of monitoring and monitoring at a plurality of locations can be realized at low cost.
In addition, the optical monitoring devices 1 and 60 have no electrical operation unit other than the optical pulse tester 50 and the display unit 53 installed at the monitoring location, and there is no fear of being affected by the induced current due to lightning strikes. Therefore, if only the optical pulse tester 50 and its attached instrument are protected from the effects of induced current, the monitoring performance will be impaired even if installed in a mountainous area where lightning is likely to occur. There is no, and the flexibility of the installation location is greatly improved. For this reason, for example, it is suitable for monitoring the displacement and deformation of various natural and man-made structures such as natural slopes facing roads, ground itself forming roads, river dikes, breakwaters provided on the ocean and lakes, and bridges. . The natural objects to which the optical monitoring apparatus according to the present invention is applied are unstable formations that may collapse such as natural slopes and cliffs, rocks that may be displaced, and the like.
[0036]
In addition, this invention is not limited to the said embodiment, For example, it cannot be overemphasized that the structure of an optical fiber sensor part, a monitoring unit, etc. can be changed suitably.
[0037]
【The invention's effect】
  According to the optical monitoring device of claim 1, the optical fiber of the communication line formed by assembling one optical cable or a plurality of optical cables.Is connected to an optical fiber assigned as a dedicated monitoring line, and the connection point between the optical fiber of the optical fiber sensor and the optical fiber of the dedicated monitoring line is connected to a branch connection installed in the middle of the communication line. The inundation detection module for detecting inundation and the temperature detection module for temperature detection that are housed and provided inside the branch connector are maintenance dedicated lines that are another part of the plurality of optical fibers of the communication line. A plurality of optical fibers on the optical cable side connected to the assigned optical fiber, including the optical fiber for the monitoring dedicated line and the optical fiber for the maintenance dedicated line, can be switched and connected to the optical pulse tester, and the optical fiber sensor side The optical fiber is connected to the optical pulse tester through the optical fiber of the communication line so that the test light can enter.An optical fiber sensor is assembled, and the displacement and deformation of the monitoring object on which the optical fiber sensor is installed is monitored by optical test of the optical fiber of the optical fiber sensor (abnormality such as bending or breakage of the optical fiber). Monitoring), because it is possible to monitor the disconnection and deformation of the optical fiber of the optical fiber sensor by monitoring the line of the communication line, the line monitoring such as the disconnection of the communication line and the displacement of the monitoring object by the optical fiber sensor Deformation monitoring can be integrated and monitored by the same optical pulse tester monitoring facility. In addition, there is an excellent effect that it becomes easy to specify the position of the monitored object that has caused displacement or deformation.
[0038]
According to invention of Claim 2, the information which shows the position of the abnormal location detected from the optical fiber of the communication line, and the information which shows the position of the abnormal location detected from the optical fiber of the optical fiber sensor are both detection units. Because it is displayed on the same display unit based on the command from the optical fiber sensor, it becomes possible to easily grasp the position of the abnormal part in the entire optical line including the optical fiber of the optical fiber sensor. There is an excellent effect that the maintenance of the entire optical line including it becomes easy.
[Brief description of the drawings]
FIG. 1 is an optical wiring diagram showing an entire optical monitoring apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating an example of a configuration of a detection unit in the optical monitoring apparatus of FIG.
FIG. 3 is an optical wiring diagram showing an entire optical monitoring apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,60 ... Optical monitoring apparatus, 5,6 ... Optical cable, 10a, 10b ... Monitoring object, 11 ... Optical fiber sensor, 12 ... Optical fiber (optical fiber of an optical fiber sensor), 17, 17a, 17b, 18 ... Optical cable 50 ... Optical pulse tester (OTDR), 52 ... Detection unit, 53 ... Display unit, 64 ... Optical branching element (optical coupler), 65 ... Optical fiber.

Claims (2)

An optical monitoring device that monitors the displacement and deformation of a monitoring object (10), such as a natural object or an artificial structure, with light,
The optical fiber of the optical fiber sensor (11) installed on the monitoring object and causing the optical fiber (12) to be broken or deformed by the displacement or deformation of the monitoring object is one optical cable (5) or a plurality of cables. A plurality of optical fibers (17, 17a, 17b, 18) of a communication line formed by assembling the optical cables, and connected to an optical fiber (17a) allocated as a monitoring dedicated line, and the optical fiber A connection point (19) between the optical fiber of the sensor and the optical fiber of the monitoring dedicated line is accommodated in the branch connection body (9) installed in the middle of the communication line, and is immersed in the branch connection body. An optical flooding module (40) for detection and a temperature detection module for temperature detection are allocated as maintenance dedicated lines that are another part of the plurality of optical fibers of the communication line. Is connected to the bar (17b), a plurality of optical fibers of the optical cable side including the optical fiber of the optical fiber and the maintenance dedicated line of said monitoring dedicated line is switchable connected to the optical pulse tester (50), An optical monitoring device (1), wherein the optical fiber on the optical fiber sensor side is connected to the optical pulse tester through the optical fiber of the communication line so that test light can enter. 60).   From the observation result of the return light of the test light incident on the optical fiber of the communication line to the optical pulse tester, the abnormal point that caused the breakage or deformation of the optical fiber of the communication line and the optical fiber on the optical fiber sensor side was determined. The light monitoring apparatus according to claim 1, further comprising: a detection unit (52) for detecting, and a display unit (53) for displaying the position of the abnormal location based on a command from the detection unit.

Images